Belt



Oct. 30, 1934. D. REPONY ET AL BELT Filed Sept. 2, 1932 2 Sheets-Sheet l INVENToRs DAN/fz /PfPo/vy JOHN TT s ATToR Y Patented @et 3b, il@

Baur

Del muy,

tan, Inc., Passat Jersey Application September 2,

Clifton, and John Nutley, N. J'., assignors to Baybest Il. Matthews. osta. corporation ci' New 1932, Serial No. 631,488

More particular the invention relates to the manufacture of belting by the assemblyl of successive layers which have been so treated as to exhibit diierent capacities for stretch when assembled into a belt, and to apparatus for treating the layers to control their capacity for stretch' and for combining them in such condition.

Although the art of making belts for power transmission is one which is almost as old as power-driven machinery, and although for nearly seventy-rive years laminated belts have been made by cementing together with rubber layers oi cloth such as canvas duck. there has, during all this timeprior to our invention, been considerable dimculty experienced with such belts, due to ply separation. It has been suggested for many years before our invention that this ply separation, bootlegging, as it is called, is due at least in part to the alternating strain resulting from the passage of the belt successively vover the curved pulleys and along a straight path between the' pulleys. Nevertheless, no satisfactory way has been discovered by which this alternating strain could be avoided, and the dimculty with ply separation has continued.

Other dimculties which heretofore have been inherent in such belts and have seriously limited 'their useful lifel are the pulling out oi fasteners, whether stitchings, splicing, or metallic fasteners, and the breaking oi outside plies or of warp threads in the outside plies. All of these dimculties we have overcome in the belt described and claimed in our co-pending application Ser. No. '702,496 iiled December 5th, 1933.

It is, accordingly, an object of the present invention to provide methodand apparatus for making such belts which is emcient, economical, and capable of commercial use in the manufacture of belting `on a large scale. A further object of our invention is to provide for manufacturing belting in any length, endless or to be cut and stapled, or spliced to form a belt oi any desired length. v According to our present invention, the belt is preferably so constructed that the greatest tension comes upon the inner layers at or near the dragged ahead of the outer layers is thereby overcome.

If the relative stretch and length of the sucwhich it is to cessive layers are properly adjusted, having regard i'or the diameter of the driving pulley over oi' all of the layers o1' the belt where they are curved around the pulally reaches that of the 'We are aware that prior to our it is not intended to, and in fact does not relieve the outer layers oi the belt from the maximum stress and tbnsion, nor prevent the destructive shifting action when the belt is driven over a pulley. We are aware, also, that it has been suggested to manufacture endless laminated belts by pulleys so that each layer is successively longer than the precedas they come over the curvature of the pulley the inner face of the belt.

In the accompanying drawings we have ent invention, l cording to our invention. These are intended to be only exemplary and are shown for the purpose of illustrating the principle and a preierred embodiment of the invention.

Fig. 1 is a longitudinal section of a belt made according to the. present invention;

Fig. 2 is a diagrammatic view, in side elevation, of a device adapted for manufacturing belting according to the present invention Fig. 3 is a diagrammatic view in longitudinal section of another type oi.' apparatus suitable for use in manufacturing baiting according to the Present invention;

.layers is substantially greater Fig. 4 is a view similar to Fig. 3, showing a section of a slightly modified form of apparatus;

Fig. 5 is a diagrammatic view in longitudinal section of still another type of apparatus; and

Figs. 6 and 'T are detail views in plan and cross-section, respectively, illustrating the corrugating device of the apparatus illustrated in Fig. 5.

Referring flrst to Fig. 1, in which we have shown a preferred embodiment of the belting made according to the present invention, it will be observed that in the curved'portion indicated by the reference character 10, the successive layers of duck of which the belting is made show substantially equal crimp, whereas on the fiat portion of the belt indicated by character l1, the crimp of the warp in the outer than that of the This is one way of securing the defor stretch. When inner layers. sired graduation in capacity the belting is made with the same or similar fab-l ric in each of the layers, this effect may be obtained either by joining the layers on a curve or in other manner eifecting a smooth adhesion between layers, one of which is slightly longer than the other, or by stretching the successive layers progressively more from the outer toward the inner face of the belt, and securing the layers together while the inner ones are thus stretched. Another simple method of attaining this result is to utilize for the successive layers fabrics which are specially woven to elongation under a given tension.

In either case, the belt may be formed and vulcanized in a fiat press, but in the former case, the finished belt will have a natural curvature'when relaxed, whereas in the latter case,'in the fully relaxed condition, the belt will tend to lie out at, but since under tension the outer layers will stretch more readily than the inner, this belt also will have, under tension, a natural curvature which will cause it to hug the pulleys in the same manner as belting made on a curve, or byprogressive stretching of the innen layers of fabric, etc. i

By natural curvature, we mean, of course, a tendency to assume a curved, rather than a fiat, condition, that is to say, the internal stresses will be most nearly balanced' when the belt is in curved form, rather than when it is straight, and this may be demonstrated by the relative magnitude of forces which are required to bend the belt toward and away from any given curvature under a given tension.

'When the belt as illustrated, for example in Fig. l, is put into service, it is found not only that it will serve very much longer without ply"'\sep aration or other serious deterioration, but that because of its inherent tendency to hug the pui ley, because of its natural curvature, it will transmit a given power with lighter bearing loads,

that is, with less tension between the pulleys, or with smaller pulleys than would be required under Vthe practice which has heretofore been regarded as standard.

It is also found that in service the primary load falls upon the inner plies of the belt. If the belt is properly designed for the pulleys on which it is used, the stretch of the outer plies which results from exing around the pulleys will result in a tension upon thcfie plies which will approximate, or `will be progressively slightly less than, the tension on the` inner'plies. The tension will be distributed among the plies in proportion to their resistance to the amount of stretch which the reference l provide successively more invasie occurs. When the outer plies stretch sumciently easily it follows that between the pulleys the powerv is transmitted primarily by the inner plies, supported to a lesser extent by theouter plies. This is in contrast, of course, to 'belts as made heretofore, in which the tension is greatest upon the outerplies and particularly on the curvature around the pulleys the stretch of the outer plies is sharply increased while the innermost plies are relaxed or even compressed.

In referring above to the progressive increase in length or in capacity forv stretch, etc., we do not intend to imply that it is essential that this change occur in every case from ply to ply. On the contrary, we have found it best to make the inner ply longer than would give a uniform progressive change, e. g., of substantially the same length and stretch as the next outer ply, and then to make the remaining plies successively longer, or with -successively greater stretch as the outside of the belt is approached. In this way, the irrnermost ply, which is subjected to frictional wear onV the surface of the pulleys, may be relieved from van important part of the tension which would be thrown thereon if the length of all plies were Kadjusted so that each is equally and progressively longer than the next, and the second ply of the belt may even take a greater part of the tension contacts with the face of the pulley. Similarly, in some cases, other plies in the belt may be adjusted less or more than would be theoretically required. We have found that except for the relief of the inner ply it is ordinarily desirable to adjust fully the layers of the belt by regular and progressive increases from ply to ply of length or capacity for stretch. y

As has already been suggested above, the belt of our invention embodying these characteristics may be made in various dierent ways. The rst, which has been suggested above, is the utilization of different fabrics which, from`an inner ply toward the outer, each is possessed of a slightly greater capacity for stretch. When this expedient is adopted, the belt may be made substantially according to present practice, except that care should be taken that the plies with the greater capacities for stretch are not excessively stretched during the plying up process.

A second method of manufacture is illustrated in Fig.,2. In this case, the inner ply` 13, or preferably the two inner plies which have previously been joined, e. g., by means of a calender not shown, are fed onto a table 14, and under a heavy hobnail press roll l5, to a pulling device 16. In the present case, this pulling device is illustrated as consisting of a pair of calender rolls 1'7 and 18 adapted to be moved intermittently. The end of the ply or plies 13 is engaged between the rolls 1'7 and 18, and at the same time the ply or than the innermost ply which table 1,4, e. g., by means of an hydraulically operated clamp 19. The stretching device 16 is then operated to produce a predetermined elongation in the length of the ply 13 which is upon the table id, and fed from between the feed rolls 21 and led along the table 14 on top of the ply or plies 13 smoothly, but without tension. One or both of the plies 13 and 20 preferably have previously been frictioned or impregnated with rubber; if not, the impregnation should be effected upon the table 14, before the ply 20.is laid thereon. The press roll 15 is then moved along the table so as to Join securely the two plies 13 and 20 alongthe entire the next outer ply 20 is then ,and when manually moved further to apparatus, alter which it length oi the table. We prefer to use a hobnail roll for this purpose because of the greater pressure which can be eileeted at spaced points in this manner, and because it is unnecessary to eiect complete adhesion at this time. In the apparatusillustrated, the movement of, the press roll is eiiected mechanically by means of a screw shaft 22 mounted in bearing blocks 23 and 2 4, and driven, for example, by a shaft 25 through the pinion gears 26. The screw shaft 22 operates in a threaded block 27 on the end of the press roll, and serves to drag the roll along the table le until the block 27 contacts with the reversing Y lever 2s. When this lever 28 is moved by the block 2l, it 'serves to operate a reversing clutch notshown, and thereby 'to move the roll back again over the table le until the clutch lever 29 is operated, which lever is moved automatically by the block 27 to disconnect the reversing clutch reengage the clutch for forward operation.

It will be observed that when the roll 15 is in its extreme left hand position, it is directly over the carriage roll 30, so that when the clamp 19 has been released, the combined plies 13 and 20 may be drawn between these rolls. Instead oiJ this arrangement, the table 14 may be somewhat depressed so as to leave a free place through which the plies may be drawn alter the move?- ment of the press roll l5 is complete. v

In the preferred embodiment as illustrated. the combined plies, after leaving' the table 14, are passed through the calender 16 further to join the layers of duch. The rolls of the calender may be so arranged that the combined layers i3 and 2li are exed around one of the press rolls when they pass through the bieht of the calender, the outer ply 20, being next to the roll around which it is flexedthat is, on the inside curve. After calender-lng in this manner to securely press the two layers together, they may be vulcanized, as usual, in a ilat belting press, preierably under tension sumcient to smooth out both plies, or with some advantage may be tightly rolled with a resilient sheet metal liner between the turns on the roll, and vulcanized in roll lori-n.

As described above, the belt would consist of only three plies. Obviously, the apparatus may be duplicated so that instead oi' feeding directly from the table 1d or the calender itl to a beltincI press, etc., the combined plies 13 and 2o may be fed to a second similar device in which both pliesvare suitably stretched and another slack ply secured thereon, and this may be repeated several times until the desired number of plies have been built up: or where repetitiomof the apparatus is objectionable, a suitable length of belting may be formed by passage through the may be againA fed through, this time taking the place of the ply 13 and having another ply 20 secured thereon. In this manner, also, endless belts may be made by drawing the ply 20 out to a suitable length andreturnine its ends along the table 14 beneath the ply 20, so that it corresponds to the ply 13 as shown-in Fig. 2.

In Fig. 3, the apparatus consists of a series oi.7 press or calender rolls 40, 41, i2 and 43, etc., which are geared together so that each is driven at a slightly faster rate than the preceding one. An inner layer or layers are fed between the initial press or feed rolls 40 at a rate controlled by the sneed at which said rolls are driven. This layer. after joining the next layer 46, passes therewith through the calender 4l. The comand 46 are then joined by an other layer 4s, and together these pass through the calender 42. This may be repeated as often as there are plies to be built up. As will be readily understood from what has been said above, the diilerence in speed between each successive calin a stretching of the ply, or combined plies, between the calenders. and when hese are combined with the next ply which is slack condition, the desired difference in relaxed length or capacity for stretch may be achieved. I

As in the case of the apparatus shown in Fig.

bined layers 44 2, the combined layers produced by the calender 41 may, after a suitable length has been produced, be returned through the rolls il) and ti1 to have an additional ply secured thereon instead of passing successively through a series of rolls d0, 4l, 42, etc.; and similarly, also, an endless belt may be produced by drawing out a suitable length oi' the ply d6 and passinar it through the rolls l0 and 4l, building up ply on ply by continuous passare o the belt therethrough until the desired thickness has been produced.

l'n Fis. e, we have apparatus similar to illustrated a portion of an mi) that 'shown in Fig. 3. in which, instead oi calenders operating at a difierent speed to stretch the lower ply or plies, the calender may be operated at the saine speed, or with slack goods between successive rolls or calenders, and the diilerence in length oi successive plies may be accomplished by combining the plies upon the circumference of the press roll, e. u., of the calender il, and by flexing the combined layers closely around the roll All while they are being pdssed through the bisht of the calender.

In this case, also. the units may be multiplied asshown in Fig. 3, or" a given length or an endless belt may be produced by repeated passage through a single unit. M5

ln Fia. 5, the strip di is fed between the press rolls do, as in lille. 3. In this case. however, the nent set of rolls, instead oi being smooth, as in the caseot the calender il ol iria. 3, comprises a corrugated roll or rolls 50; and sprocket chains im 5l with pins 52 rotate beside the calender rolls 50, so that the pins 52 move over the surface oi' the lower ply or plies de, and at substantially the saine rate therewith, and carry the sluclr ply 4t, assurina a slight corrugation ci said ply which 125 will correspond with the corrugatiom of the roll 50. Thus, when the superposed plies are joined by the pressure oi the roll 50 at spaced points, there will be a certain amount of slaclr leit in the upper ply, and when the belting thus built up is subsequently vulcanized, profe bly under tension, this slack will be teiten up and a smooth belt with the desired compensation will result.

We are aware that numerous other apparatus and methods may be used for the manufacture oi a belt according to our invention, and that many changes and modifications may be made from the above description and the annexed drawample of the other baiting materials, as 'skilled in the art. Although greatest advantage in power .of belting, as for example,

ilarly, we have referred to textile fabrics for exmater'ial treated by this process and apparatus in the manufacture or baiting, but it is to be' understood that the process and apparatus of our invention may be used with any will be obvious to those the invention is o transmission belts, because of the relatively great stresses which result from the power applied to the belt,the in vention is none the less applicable to other types conveyor belts, etc.

What we claim is:

winch comprises flexing a layer of belting material over a surface curved on a small radius relative to that of a circle with circumference equal to the length of the belt to be formed, applying a second layer of beiting material to the first upon the curved surface and securing the ,superposed layers together by surface adhesion progressively over substantially their entire area while they are on such curve.

2. The method as defined in claim l, in which at least one of said layers of belting material is covered with alayer of cementing rubber to which the other is secured by pressure, and the resulting belt is vulcanized while hat, but under tension suiiicient to smooth all of the layers.

3. The method of forming a laminated belt which comprisesv stretching a layer ol belting material, securing thereon while so stretched another layer of belting material which is -not stretched to an equal extent.

4;. A method oi forming e laminated-belt which comprises stretching over a supporting surface a layer of belting material which in use is to the face of the pulley on which it runs, a relatively slack layer of belting be near laying thereon terapia means for supplying use is to be farther from the securing the layers together material which in face of the pulley,

throughout their length, and thereafter releasing' the tension thereon.

5. The method of making a laminated belt which comprises weaving a strip of fabric with relatively great crimp of the longitudinal threads, weaving another strip of fabric with a lesser crimp of the longitudinal' threads, and securing Said strips together throughout their length.

6. A method of making a laminated belt which comprises corrugating a strip of belting material, feeding it to a second layer of belting material which is held more nea' ly straight, securing the two together at the nodes of the resulting corrugations formed in the rst layer, and thereafter securing said strips together over substantially their entire surface.

7. An apparatus for making belts comprising means for stretching a length o belting material, lthereon a second layer o belting material slack relative to the iirst, means for securing said layers together while the iirst is still stretched, andbelting. l

8. .An apparatus for making belting which comprises means for applying an adhesive to a strip of belting material, a forming roll of small circumference as compared with the length of the belt being made, means for flexing said strip over only a part of the circumference of said roll, means for applying a second strip on top of the rst, so that it passes therewith over and around a part of said forming roll, and means for securing said strips together while they are on said forming roll.

DANIEL RWONY.

JOM H. MATI'IEWS. 

